Nearly every holiday shopping season has a must-have toy that parents scramble to get under the Christmas tree – a Tickle-Me Elmo, Furby or Zhu Zhu Pet that sends them on a desperate cross-county mall expedition or a last-minute eBay hunt.

This year, forecasters expect the hottest holiday toy to be one based on the silver screen: Make way for the Snow Glow Elsa Doll, a 15-inch version of the heroine from Disney’s smash hit “Frozen” that costs $39.99, sports a light-up dress, a “magical snowflake necklace” and belts out the film’s ballad, “Let it Go.”

While Elsa is expected to reign supreme at the cash register, analysts say that many other must-have toys this year also have tie-ins to some of the year’s biggest movies, including blockbusters such as “Teenage Mutant Ninja Turtles,” “The Lego Movie” and “Transformers: Age of Extinction.”

As the lines blur between screen time and playtime, toy-makers and media firms are finding that there is lucrative business in building a beloved character that children can enjoy everywhere: on tablet apps, DVDs and as a lifelike toy.

“It really just shows that what kids watch, they inevitably want to interact with,” said Matthew Hudak, an analyst for Euromonitor International.

Stores such as Toys R Us and Wal-Mart are hoping that these movie-themed toys will help them deliver strong holiday sales in a retail environment that economists say is likely to be characterized by deep discounts and fierce price competition.

Richard Barry, chief merchandising officer at Toys R Us, said that the anticipated popularity of movie-inspired toys is in part based on the popularity of this year’s slate of kid-focused films. But, he said, toy manufacturers also have become more innovative and made their toys more lifelike.

“That is the secret here, the fact that you can bring to life in a very clear way the essence of the characters that are in the movie,” Barry said.

Take Disney’s Infinity Marvel Super Heroes 2.0 Starter Pack. It includes three action figures and a video game. When you place the chip-enabled action figure on a special base attached to a gaming console, the character becomes part of the onscreen action. The game includes characters from “Guardians of the Galaxy” and other popular Marvel Comics films.

Perhaps the clearest sign this year of the synergy between the box office and toy store shelves has been the surge of Lego, the Danish company whose building blocks have been a fixture in playrooms for decades.

“The Lego Movie” has raked in $258 million in the United States, making it the third-highest grossing film this year. Amid the movie’s massive popularity, the toy-maker’s sales surged 11 percent in the first six months of the year, allowing it to pass rival Mattel in sales and profits for the first time to become the world’s largest toy-maker. Lego has a sequel expected to hit theaters in May 2017.

This holiday season, Toys R Us expects the Lego Fusion Town Master to be among its most coveted items. Aimed at 7- to 12-year-olds, the set allows kids to build stores and fire stations and then manage their creations with a smartphone or tablet app.

“Frozen” opened in November 2013, too late to pick up enough steam before last year’s holiday shopping frenzy to land on many Christmas lists. But now that it has become the fifth-highest-grossing movie of all time, expect plenty of requests for Elsa and her sister, Anna, not only in doll form but tiaras, boom boxes and nail-polish sets.